This invention relates to a contact structure of a combination switch for effecting operations such as the lighting of headlamps of a vehicle, the lighting of turn signal lamps and the driving of wipers.
A related combination switch is shown in FIGS. 3 and 4. As shown in FIGS. 3 and 4, this combination switch 1′ is provided with an operating lever 2′, projected from a steering column (not shown), and includes a plurality of switches 3, 4, 5 and 6 which can be switched by various kinds operations of the operating lever 2′. Each of these switches 3, 4, 5 and 6 includes a moving contact 8 mounted on a contact holding member 7, and a fixed contact 10 provided on a contact board 9.
As shown in FIGS. 3 and 4, the moving contact 8 is urged toward the fixed contact 10 by a spring force of a spring 11 which is provided between the moving contact 8 and the contact holding member 7. The moving contact 8 is slid over the contact board 9 which includes the fixed contacts 10 by operating the operating lever 2′. Each fixed contact 10 is formed, using a part of an associated bus bar insert molded in the contact board 9. Namely, the contact board 9 is formed by insert molding the bus bars (products formed by pressing) in a resin, and circuit wiring, the fixed contacts 10, a connector portion and so on are formed by the bus bars. In the drawings, reference numeral 12 denotes an under cover.
However, in the contact structure of the above related combination switch 1′, the fixed contacts 10 are formed, using the bus bars insert molded in the contact board 9, and therefore the contact structure of the combination switch 1′ is complicated, large in size and high in cost. Namely, the bus bars are thick and wide, and since such bus bars are insert molded, the contact board 9 has a large size. In the case where a large amount of circuit wiring is installed in the contact board 9, the contact board 9 must be divided into two board part members 9a and 9b as in the above related example, and the two board part members 9a and 9b are combined together, and as a result the overall structure becomes more complicated and larger in size.
And besides, the bus bars themselves are costly, and also the insert molding is costly, and therefore the cost further increases. Furthermore, in the case where the contact board 9 is formed by the two board part members 9a and 9b as described above, such two insert molded products must be prepared and combined together, so that the cost further increases.